Dr. A. Gunther on the Fauna of Madagascar. 71 



Chamcehon Willsii. (PI. VI.) 



This species is closely allied to Chamcehon minor (Ann. & 

 Mag. Nat. Hist. 1879, vol. iv. p. 246), bat differs by its 

 broader head, which is quite flat between the orbits in the 

 female, and very slightly concave in the male, whilst in Cha- 

 mafleon minor the upperside of the head is deeply concave in 

 both sexes. Snout of the adult male produced into two flat 

 compressed horns, divergent in front and covered with large 

 scutes, of which one in the middle of the upper edge projects 

 like a prong ; the horns are much less approximate at the 

 base than in Chamadeon miner ; they are, as usual, absent in 

 the female. Occipital region with a rounded margin behind, 

 without any prominent parietal crest, which in Chamadeon 

 minor is rather conspicuous. No lateral occipital flaps. A 

 dorsal crest is present in the male only, and consists of a 

 few conical tubercles which occupy the nape of the neck. No 

 gular or ventral median series of tubercles. Head covered 

 with small, flat, irregular scutes ; scutes of the body uniform, 

 flat, scarcely smaller than those of the head, but much larger 

 than in Chamadton minor. Heel without spur or promi- 

 nence. 



Dark greenish or yellowish, with a white streak along the 

 median line of the throat and abdomen ; a narrow yellow ring 

 round the middle of the foot; a similar marking is indicated 

 by one or two small spots on the hand ; female with an inter- 

 rupted yellow line along the hinder side of the hind limb and 

 continued for a short distance on each side of the tail. 



Four specimens were collected, two adult males and two 

 females. The larger of the males is 6^ inches long, the tail 

 measuring 3^ inches. The fully adult female is smaller, 

 measuring only 4^ inches, of which the tail takes one half. 



Liojdiis Imerince. 



Scales in nineteen series. Head short, snout rather pointed ; 

 eye small, with round pupil. Rostral shield protruding, 

 extending on to the upper surface of the head ; frontals small, 

 the anterior scarcely one half the size of the posterior ; ver- 

 tical longer than broad ; occipitals as long as vertical and 

 postfrontals together. Loreal short ; one prasocular, not 

 reaching to the upper surface of the head ; two postoculars. 

 Eight upper labials, the fourth and fifth entering the orbit. 

 Temporals 1+2 + 5, the foremost in contact with the lower 

 pustoeular only. Three lower labials in contact with the 

 anteiior chin-shields. 



